1. Field of the Invention
The present invention relates to methods and structures by which improved distribution of chemical solutions, such as plating solutions, etching solutions, or electroetching solutions, is provided to a pad/substrate interface in a plating or etching apparatus that uses an anode/pad assembly. According to the invention, a system of channels is designed under the pad to distribute the solution more evenly and to prevent the solution from coming directly from the pad support member and hitting the substrate surface.
2. Description of Related Art
There are numerous processing steps in the fabrication of high performance integrated circuits (ICs), packages, magnetic film heads, thin film display units, and the like. One important step is to deposit, remove, or planarize a conductive or insulative material on a work piece, such as a semiconductor substrate, or perform various combinations of such depositing, removing and planarizing operations. Deposition of conductive materials such as copper, gold, nickel, rhodium, platinum, magnetic materials, and their various alloys may be performed, for example, by electrodeposition.
In inlaid metal technology, a workpiece, such as a substrate 10 shown in FIG. 1a, may consist of various topographical features such as channels 14 and vias 12 etched in a suitable dielectric material 16. The surface of the etched dielectric material 16 is generally coated with a suitable adhesion/barrier film layer 18. Over the barrier layer 18, a suitable plating base layer 20, often called a xe2x80x9cseed layerxe2x80x9d, is deposited. A conductive layer 22 is then applied over the plating base layer to fill, and preferably over-fill, the vias 12 and channels 14 etched in the dielectric material 16 as shown in FIG. 1c. 
The conductive material may be, for example, Cu deposited by way of a chamber-type device 100 (generally shown in FIG. 1b). The chamber device 100 includes a deposition chamber 102, which contains an anode 104 and electrolyte 106. The anode 104 may be attached to the bottom of the chamber 102.
A holder 108 holds the workpiece, such as the substrate 10. For a detailed description of the holder, reference can be made to the assignee""s co-pending application Ser. No. 09/472, 523, entitled xe2x80x9cWork Piece Carrier Head For Plating and Polishingxe2x80x9d filed Dec. 27, 1999, the specification of which is incorporated by reference herein as non-essential matter.
For the deposition process, the substrate 10 is typically immersed in the electrolyte 106 with the aid of the holder 108, which also provides a way of electrically contacting the substrate 10. By applying a potential difference between the anode 104 and the substrate 10 (i.e., the cathode), materials may be deposited on or removed from the substrate. For example, when the anode is more positive than the substrate, copper may be deposited on the substrate 10. If the anode is more negative than the substrate, however, copper may be etched or removed from the substrate. To aid electrolyte agitation and enhance mass transfer, the substrate holder 108 may include a rotatable shaft 112 such that the substrate holder 108 and the substrate 10 can be rotated. The substrate 10 is typically spaced apart from the anode 104 at a distance of at least about 10 mm; this distance may, however, be as great as about 300 mm. The surface of the substrate 10 may contain topographic features, such as the vias 12 and channels 14 illustrated in FIG. 1a. After performing material deposition to fill the various features/cavities using electrolyte containing leveling additives, a variation in the thickness of the deposited conductive material 22 inevitably occurs over the surface of the substrate. The undesirable excess conductive material over the field region is called xe2x80x9coverburdenxe2x80x9d. This variation in thickness or xe2x80x9coverburdenxe2x80x9d is shown in FIG. 1c with reference to portions 22a and 22b. 
After depositing the conductive material 22 on the top surface of the substrate 10, the substrate 10 is typically transferred to a chemical mechanical polishing (CMP) apparatus in order to polish, planarize, or both polish and planarize the same surface. FIG. 2a illustrates one possible version of a conventional CMP apparatus 200 used to polish/planarize the substrate 10 and/or electrically isolate the deposited conductive material within the particular features located thereon. The substrate holder 208, which may be similar to the holder 108 described above, holds and positions the substrate 10 in close proximity to a belt-shaped CMP pad 214. The belt-shaped pad 214 is adapted to rotate in an endless loop fashion about rollers 216. The polishing/planarizing process occurs when the rollers 216 rotate and the pad 214 is moved with a circular motion while making contact with the surface of the substrate 10. A conventional slurry may also be applied to the pad 214 while the substrate 10 is being polished. The substrate surface after polishing is shown in FIG. 2b. 
The conventional method for depositing a conductive material produces large variations in material overburden across the substrate as shown in FIG. 1c. The conventional CMP of this large overburden causes defects on the substrate 10 such as dishing 22c and dielectric erosion 16c also shown in FIG. 2b. It also is responsible for low substrate processing throughput, which is a major source of manufacturing yield loss.
There is therefore a need for an apparatus that can reduce the time needed during the planarization phase of the fabrication process, and that can simplify the planarization phase itself. In other words, a more efficient and effective method and apparatus for depositing a conductive material on a substrate is needed. Several improved pad designs and structures are disclosed herein that can be used for depositing conductive material with a very uniform material overburden on a surface of a substrate. The pad design may also be used in a polishing technique such as CMP.
It is an object of the present invention to provide an improved method and an improved apparatus for performing any of depositing, removing, polishing, and/or modifying operations on conductive material, which is to be applied to or has been applied on a substrate. The improved method eliminates direct communication of electrolyte fluid flow from a pad support member to the substrate surface and permits electrolyte fluid to be supplied at greater pressures and flow rates.
This and other objects of the present invention are obtained by a particular apparatus which is capable of assisting in controlling an electrolyte flow and distribution of an electric field, a magnetic field, or an electromagnetic field in order to process a substrate. The apparatus includes a support member having a top surface and a bottom surface, the support member containing at least one support member electrolyte channel. Each support member electrolyte channel forms a passage between the top surface and the bottom surface of the support member and allows the electrolyte to flow therethrough. The apparatus also includes a pad, attachable to the support member, which contains at least one set of pad electrolyte channels also allowing for electrolyte flow therethrough to the substrate. Each support member electrolyte channel is connected to one set of pad electrolyte channels by a particular fluid distribution structure.
According to one embodiment of the invention, each support member electrolyte channel is one of a plurality of support member electrolyte channels, and each set of pad electrolyte channels is one of a plurality of sets of pad electrolyte channels.
The fluid distribution structure includes distribution channels interconnecting each support member electrolyte channel to a set of pad electrolyte channels. In one embodiment, the distribution channels are formed in the pad, while in another embodiment, the distribution channels are recessed channels defined in a surface of the pad facing a top surface of the support member.
One preferred embodiment is constructed so as to have an element interposed between the support member and the pad in which the fluid distribution structure is defined. In this case, the element is a platen having channels defined therein. The channels defined in the platen interconnect each support member electrolyte channel to the one set of pad electrolyte channels. No support member electrolyte channel is aligned with any of the pad electrolyte channels in any of the preferred embodiments.
In the preferred embodiments, each of the distribution channels extends substantially horizontally between the at least one support member electrolyte channel and one pad electrolyte channel of the set of pad electrolyte channels.
An improved method of assisting in control of an electrolyte flow and distribution of an electric field, a magnetic field, or an electromagnetic field for processing a substrate is also provided.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.